Optic flow and the surface patch
David Young (U. of Sussex, UK)
The instantaneous position, orientation and motion of a planar surface
relative to an observer can be described fully using 11 parameters.
However, not all of these are needed in order to interact successfully
with the surface, whilst perceptual information such as optic flow will
normally only provide some constraints on them. The information needed
or available is equivalent to restricting the parameters to a subspace
of the full parameter space. In this talk I look at ways of
characterising such spatiotemporal subspaces and hence clarifying the
possible role of optic flow in the control of motion relative to a
surface. In particular I consider the subspaces associated with first
and second order optic flow, and how this information allows tasks such
as docking manoeuvres to be carried out successfully. I will also
comment on the design and interpretation of experiments intended to
investigate the use of optic flow by the human visual system.